Magnetic core structure



R E R E U A M L MAGNETIC CORE STRUCTURE Filed Jul},- 150 1942 Jizde/zbf' Leopold Maueref a M, M p

Patented June 12, 1945 MAGNETIC CORE STRUCTURE Leopold Mauerer, Chicago, 111., assignor to Jefferson Electric Company, Bellwood, 111., a corporation of Illinois Application July 30, 1942, Serial No. 452,920

9 Claims.

a way that air gaps are minimized or eliminated from the flux paths.

An object of this invention is to provide a magnetic core structure including cooperating stacks of laminations and core clamps adapted to force the stacks into closely abutted relation during assembly, and thereafter to hold the stacks in such closely abutted relation.

Another object of this invention is to provide a magnetic core structure including core clamps or holding elements which not only force the core parts into close assembled relation, but' which are also inexpensive and easy to assemble in production.

Further objects and advantages of the presen invention will be apparent from the following description, reference being had to the accompanying drawing wherein structures illustrative of the invention are shown.

In the drawing Figure 1 is a broken elevation of a magnetic core provided with a form of clamping means embodying the present improvements;

Figure 2 is a sectional view taken on line 2-2 of Figure 1 and showing the structure prior to the drawing of the core sections into closely. abutting relation;

Figure 3 is a similar section view showing the core sections drawn into closely abutting relation;

Figure 4 is a broken elevation of cooperating core sections provided with a modified form of clamping means;

Figure 5 is a sectional view taken on line 5-5 of Figure 4;

Figure 6 is a similar sectional view showing the core sections drawn into closely abutting relation;

Figure 7 is a broken elevation of cooperating core sections provided with a further modified form of clamping means;

Figure 8 is a sectional view taken on line 8-8 of Figure 7;

Figure 9 is an elevation of a detached clamping member oi. modified structure;

Figure 10 is'a broken elevation of a core with the modified clamping means in position and after deformation to tighten the joint between the core sections; and

Figure 11 is an end elevation of a core showing a pair of the clamping members thereon but prior to deformation of the members.

In Figures 1 to 3 of, the drawing a magnetic core is shown comprising two L shaped sections indicated generally by the numerals l0 and II, each of which is formed of laminations II. In order, to provide a low reluctance core path it is desirable that the contacting surfaces of the core sections it) and ll b drawn into and retained in closely abutting relation. For the purpose of uniting the core sections after a winding or windings (not shown) have been assembled thereon and for drawing the sections into such closely abutting relation, two pairs of clamping members are shown .in Figure 1. The clamping members are similar and hence one pair only will be described. Each of the clamping members comprises two similar straps I3 which are perforated to receive a rivet H by means of which corre-' sponding ends of the straps 13 are attached to one of the core sections and by means of which the laminations of that section may be retained in assembled relation.

The straps i3 span the adjacent joint defined by the surfaces I5 and IQ of the sections i0 and i l respectively, as shown in Figure 2, and overlie the adjacent portions of the othercore section ii. The overlying portions of the straps i3 are provided each witha slot I! for receiving the ends of a pin II which projects from opposite sides of the core section 1 I. Communicating with the slot I! are slits I9 formed to provide tongues 20 which are bent outwardly initially from the plane of the respective straps i3. When the core sections 10 and ii are in the relation shown in Figure 2, the pin i8 is inserted into a receivin aperture formed in section Ii with the ends of the pin projecting beyond thefaces of the section,

-'I'he straps l3 being of suitable metal, the tongues can be deformed from the normal or initial position. shown in Figure 2 into or toward the planes of the respective straps and in being so moved the free ends of the tongues abut the projecting end portions of the pin l8 and force the pin and the core section ii toward the core section III. Hence when the tongues 20 have been pressed into or substantially into the plane of the straps IS, the joint surfaces i5 and I6 of the respective core sections will be in intimate contact one with the other and will be retained in such position which is shown in Figure 3.

The wedging action accompanying the deformation of the ton ues 20 of each pair of clamp members not only effects the forcing of the respective Joint surfaces I5 and I8 into close contact for insuring a low reluctance path, but the clamps unite the core sections into a rigid unitary structure.

In the modified form of the invention illustrated in Figures 4 to 6 inclusive, U shaped core sections 2| and 22 are shown which are provided with two pairs of clamping straps for uniting the sections and drawing the Joint surfaces 23 and 24 thereof into intimate contact. Each pair of clamping members comprises straps 25 which are shown provided with outwardly turned stiffening flanges 26 along the longitudinal edges. As shown in Figure 5 a pair of plates is attached, as by means of a rivet 21, to one of the core sections. The straps 25 span the adiacent joint between the sections and overlies adjacent portions of the other core section. The overlying portions of the straps 25 are provided with slots 28 for receiving a headed abutment pin or rivet 29, the ends of which project from opposite sides of the core section 22. Each strap is provided with an integral tongue 30 which as initially formed is bowed or bent outwardly intermediate its ends as shown in Figure 5. The tongues 38 may be deformed or flattened by pressure applied thereto whereby the free ends of the tongues which abut the projecting ends of the pin 29 force the pin and core section 22 toward the section 2i and thus draw the joint surfaces 23 and 24 into closely abutting relation as shown in Figure 6. The inserted end of the pin or rivet may then be upset as shown in Fig. 6. In the latter figure the outwardly bowed portions of the tongues 30 are shown as somewhat flattened as compared with the illustrations of those members in Figure 5. In this exemplification of. the invention also the clamping action is effected by the deformation of the tongues of the clamping members as will be seen.

In Figs. '7 and 8 core sections 3| and," are shown provided with clamping members 33, the ends of which are riveted to the adjacent portions of the core sections. The intermediate portion of each clamp member comprises a pair of deformable straps 33*, which originally are spread apart sufllciently, as indicated by dotted lines in Figure 4, to enable a rivet 34 to be pressed through a perforation in the core sections 32 to further spread the straps apart to the full line position shown in Figure '7. The spreading of the straps 33 foreshortens the respective clamp members and thus draws the core sections together as in the above described illustrative embodiments of the invention. After rivet or pin 34 has been pressed into final poo.- tion for forcing the straps 33- apart, the entering end of the rivet can be upset as shown in Figure 8.

In Figures 9 to 11 inciusive another form of the improved clamping means is illustrated. In Figure 9 one of the clamps is shown in detached relation and comprises a strap 35 having rivet openings 36 therein whereby a pair of the straps can be riveted to span the joint 31 between core sections 38 and 39 as shown in Figure 11. Each of the straps 35 has perforations 40 formed therein which define longitudinal legs ll and a transverse intermediate web or bridge 42 which is bowed outwardly initially as shown in Figure 11.

After the straps have been attached in pairs to core sections across the Joint or Joints thereof that are to be closed the webs 42 are flattened or compressed toward or into the plane of the respective straps. Such deformation of the webs spreads the legs of the respective straps, foreshortening them, and draws the Joint surfaces of the core section into intimate contact as illustrated in Figure 10.

While theimproved clamping members preferably are employed in pairs at all the joints of cooperating core sections that are to be drawn into closely abutting relation, in some instances they may be used singly if desired.

It will be observed that in all forms of the invention-shown the clamping action is effected by deformation of portions of the clamp member to effect movement of the anchoring means, such as the'rivet I4 and pin I8 of Figure l, or the rivets 33 of Figure '7, one toward the other,

- thereby forcing the surfaces of the respective be'resorted to without departing from the spirit of the invention.

I claim:

1. A magnetic core structure comprising, in combination, cooperating stacks of laminations having surfaces abutted closely together to form joints therebetween and provide a closed magnetic circuit; and core clamping means including a pair of clampin elements for each joint,

the elements of each pair extending across one of said Joints on opposite sides of the stacks, fastening means securing the laminations of one of the stacks and one of said pairs of clamping elements together, means extending through the laminations of the other stack and through said pair of clamping elements, each of said clamping elements having an integral deformable portion, deformed into engagement with said last mentioned means and cooperating therewith to hold the laminations and stacks tightly together.

2. A magnetic core structure comprising, in combination, cooperating stacks of laminations and means forcing the laminations of said stacks into tight engagement and holding the laminations in position to provide a closed magnetic circuit, said means comprising clamping elements on opposite sides of the stacks and each extending across portions of each of the stacks, meansv connecting the clamping elements to the laminations of each of the stacks, and each of said clamping elements having a portion which is bent in such a maner as to hold the stacks of laminations together.

3. In a magnetic core structure having cooperating stacks of laminations, means forcing the laminations of the stacks into tight engagement and joining said stacks to provide a low reluctance joint therebetween, said means comprising strap members adjacent opposite sides of the stacks of laminations and having slots therein, means extending through one of the stacks of laminations and the strap members and securing them together, pin means extending through the other of the stacks of laminations and said slots in the strap members, and said strap memthe stacks and said end openings and securing the strap elements and laminations together, and

- means forspreading the mid-portions of the strap elements on opposite sides of said longitudinal siotsto ioreshorten the strap elements and draw the stacks tightly together.

'5. A magnetic core structure comprising, in

combination, cooperating stacks of iaminations and means Joining and effecting. close engage-' ment of the laminations of the Stacks; said means comprising strapelements adjacent opposite sides of the stacks and having longitudinal slots through the mid-portion thereof, rivets securing the ends of the strap elements to .ea'choLthe stacks of lamination, and means" opening said '7 slots transversely to eiiectioreshortening of the strap elements.

6 In a magnetic cor structure having 30 crating core sections having ioint surfaces adapt.-

curing the ends of the strap elements to each of the stacks of laminations, whereby upon deforming said bowed webs toward the plane of the respective legs the latter are spread further apart and foreshortened and the joint surfaces of the core sections are drawn closely together.

7. A magnetic core structure comprising cooperating core sections. having surfaces drawn into closely abutting relation to provide low reluctance joints between the sections, clamping means for the stacks at each joint each comprising a strap attached to one of the stacks and spanning the respective joint, 9, member projecting from the other stack, and a deformed portion carried by said strap and engaging said projecting member for maintaining said joint surfaces together. r

8. Means for. drawing and holding together joint'surfaces of a pair of cooperating core sec- 'tions, said core sections including in combination therewith, a pair oi straps secured to opposite faces of one of said sections and projecting across ed to be drawn into close engagementmeans for 7 drawing said sections together comprising strap elements adjacent opposite sides of the sections each comprising separated longitudinal legs and an integral transverse outwardly bowed web joining the mid-portions of said less and means sehave been forced into the joint and over adjacent portions of the other 3 section, abutment members projecting from. the latter section and deformed tongues carried by said straps and abutting said projectim members for forcing said surfaces-into close contact.

9. Means to: drawing ,and holding. together the joint surfaces of a Pair of coresections, said core sections including in combination therewithi a strap spanninz the joint, means for anchoring the strap to each section, and a deformable portion carried by the snap whichhasbeen deformed to draw the anchoring members one toward the other and whereby the joint surfaces cioselv abutting relation. LEOPOLD MAUERER. 

